The present invention is directed toward gravity exercise trainers suitable for use in the home, and more particularly, to exercise machines having a glide board mounted on inclined rails.
Exercise machines with an inclined board slidably mounted on a support, on which the user exercises against his or her own weight, are well known in the art. See, for example, Van Straaten U.S. Pat. No. 4,911,438, Campanaro U.S. Pat. No. 5,169,363 and Lundin U.S. Pat. No. 5,620,403.
Van Straaten and Lundin describe exercise machines including a board slidably mounted on an inclined rail which is movably connected at one end to an upright post. The inclination of the inclined rail can be adjusted by moving the connected end up or down along the post. These machines require a complicated housing to connect the inclined rail to the post into which fingers or other objects may be jammed. Also, folding for storage can be accomplished only through the awkward process of raising up the entire length of the inclined rail frame with the sliding board attached.
Campanaro describes a similar machine in which the board is slidably mounted on two inclined rails which are movably connected to an upright support structure. The inclination of the inclined rails is adjusted by attaching them to fixed hooks mounted to the upright support structure. Adjustment of the inclination of the inclined rails is awkward on this machine and the machine is unstable in that the inclined rails can be dislodged from the hooks with a relatively small amount of force. It is also incapable of folding or storage as a single compact unit.
Foldable gravity trainers are known to the art. For example, the Total Gym manual, published by Total Gym Fitness, Ltd, describes an exercise machine with a board slidably mounted on a pair of inclined rails. The inclination of the rails can be adjusted by moving one end along an upright post and locking the rails into place with a locking pin. The exercise machine may be folded by lowering the rails so that they are approximately horizontal, and folding them at a hinge located near the midpoint of the rails.
The exercise machine described in the Total Gym manual, if used improperly, can produce serious injury. For example, if the user attempts to fold the machine while holding one of the rails near the folding hinge, it is fairly easy for the user to catch his or her finger between the rails as they fold together, resulting in serious injury to the finger.
Injury may also occur if the user attempts to operate the machine while the rails are in the lowest (i.e. approximately horizontal) position, as this configuration can permit the upright post to fall toward the board and the user thereon.
It is also known to use hard plastic or metallic wheels having concave outer surfaces for mounting sliding boards upon rails of exercise machines. Such wheels are useful because they can resist movement of the sliding board other than along the axes of the rails. However, these wheels often provide an uncomfortable ride when used to roll on a hard metallic rail surface which is not chrome plated.
Wheels having a resilient convex outer surface are known in the art. However multiple opposing wheels must be used to hold a sliding board to a rail.